Apple doesn't allow the user to set an app as "don't kill even if not focused for a while" ? Android user here
On Android it's not automatic or automated and the user has to do it by hand himself (for obvious reasons); but for a few specific apps it allows them to work the way they should without needing weird permissions to emulate
> UPDATE: We record significantly increased number of app killing on Samsung's Android Pie flavor. The hints show adaptive battery being much more eager than in stock Android.
> After 3 days any unused app will not be able to start from background (e.g. alarms will not work anymore). Imagine, you won't use your alarm clock for a the weekend +1 day and bang! no alarms any more and you miss work! We strongly suggest to turn off Adaptive battery and Put apps to sleep options per instructions below.
That alarm thing has happened to me several times and is why I recommend to people to not use their phone as alarm at as a dedicated device makes much more sense.
